
\chapter{Unit modifiers}
\label{app:units}

The {\dftbp} code uses internally atomic units (with Hartree as the
energy unit). The value of every numerical property in the input is
interpreted to be in atomic units (au), unless the property carries a
modifier.

The allowed modifiers and the corresponding conversion factors are given
below.\footnote{The conversion factors listed here were calculated with double
  precision on i686-linux architecture.  Depending on your architecture, the
  values used there may deviate slightly.}  (The modifiers are case
insensitive).

{\AA}ngstr{\"o}ms may be listed as any of ``a'', ``aa'' or ``angstrom'' in the
unit modifiers.

\begin{unittable}{Length}
  \is{Angstrom}, \is{AA}, \is{A} (for {\AA}ngstr\"om) & 0.188972598857892E+01 \\
  \is{Meter}, \is{m} &  0.188972598857892E+11 \\
  \is{pm}            &  0.188972598857892E-01 \\
  \is{Bohr}, \is{au} &  1.000000000000000E+00 \\
\end{unittable}

\begin{unittable}{Mass}
\is{amu}   & 0.182288848492937E+04 \\
\is{au}    & 1.000000000000000E+00 \\
\is{da}    & 0.182288848492937E+04 \\
\is{dalton}& 0.182288848492937E+04 \\
\end{unittable}


\begin{unittable}{Volume}
  \is{Angstrom$^{{\wedge}}$3}, \is{AA$^{{\wedge}}$3}, \is{A$^{{\wedge}}$3} &
  0.674833303710415E+01 \\
  \is{meter$^{{\wedge}}$3}, \is{m$^{{\wedge}}$3} &
  0.674833303710415E+31 \\
  \is{pm$^{{\wedge}}$3} &
  0.674833303710415E-05 \\
  \is{bohr$^{{\wedge}}$3}, \is{au} &
  1.000000000000000E+00 \\
\end{unittable}

\begin{unittable}{Energy}
  \is{Rydberg}, \is{Ry} & 0.500000000000000E+00 \\
  \is{Electronvolt}, \is{eV} & 0.367493245336341E-01  \\
  \is{kcal/mol} &  0.159466838598749E-02 \\
  \is{Kelvin}, \is{K} & 0.316681534524639E-05 \\
  \is{cm\^{}-1} & 0.455633507361033E-05 \\
  \is{Joule}, \is{J} &  0.229371256497309E+18\\
  \is{Hartree}, \is{Ha}, \is{au} & 1.000000000000000E+00 \\
\end{unittable}

\begin{unittable}{Force}
  \is{eV/Angstrom}, \is{eV/AA}, \is{eV/A} & 0.194469064593167E-01 \\
  \is{Joule/meter}, \is{J/m} & 0.121378050512919E+08\\
  \is{Hartree/Bohr}, \is{Ha/Bohr}, \is{au} & 1.000000000000000E+00 \\
\end{unittable}

\begin{unittable}{Time}
  \is{femtosecond}, \is{fs} & 0.413413733365614E+02 \\
  \is{picosecond}, \is{ps} & 0.413413733365614E+05 \\
  \is{second}, \is{s} & 0.413413733365614E+17 \\
  \is{au} & 1.000000000000000E+00 \\
\end{unittable}

\begin{unittable}{Charge}
  \is{Coulomb}, \is{C} & 0.624150947960772E+19 \\
  \is{au}, \is{e} & 1.000000000000000E+00 \\
\end{unittable}

\begin{unittable}{Velocity}
  \is{au} & 1.000000000000000E+00 \\
  \is{m/s} & 0.457102857516272E-06 \\
  \is{pm/fs} & 0.457102857516272E-03\\
  \is{a/ps} & 0.457102857516272E-04\\
  \is{aa/ps} & 0.457102857516272E-04\\
  \is{angstrom/ps} & 0.457102857516272E-04\\
\end{unittable}

\begin{unittable}{Pressure}
  \is{Pa} & 0.339893208050290E-13 \\
  \is{au} & 1.000000000000000E+00 \\
\end{unittable}

\begin{unittable}{Frequency}
\is{Hz}    & 0.241888432650500E-16 \\
\is{THz}   & 0.241888432650500E-04 \\
\is{cm\^{}-1} & 0.725163330219952E-06 \\
\is{au}    & 1.000000000000000E+00 \\
\end{unittable}

\begin{unittable}{Electric field strength}
\is{v/m}   & 0.194469063788953E-11 \\
\is{au}    & 1.000000000000000E+00 \\
\end{unittable}

\begin{unittable}{Dipole moment}
\is{CoulombMeter}, \is{Cm} & 0.117947426715764E+30 \\
\is{Debye} & 0.393430238326893E+00 \\
\is{au}    & 1.000000000000000E+00 \\
\end{unittable}

\begin{unittable}{Angular units}
\is{degrees}, \is{deg}  & 1.745329251994330E-02 \\
\is{turns} & 6.283185307179586 \\
\is{gradians} & 1.570796326794897E-002 \\
\is{radians}, \is{rad} & 1.000000000000000E+00 \\
\end{unittable}
